Lumber-compatible lightweight metal construction system

ABSTRACT

The lightweight metal construction system begins with a beam formed from a single piece of cold formed sheet steel or other sheet metal which is bent lengthwise along four lines to form a triangular cross-section with two wings, side-by-side, extending from its apex. Various connectors which have lengths much shorter than the lengths of the beams are provided for attaching one beam to another. Connectors include gussets made of sheet metal or wood stud sections. The ends of the beams may be modified to form joints which are used to connect two beams together or to connect the beam to another construction material. Brackets formed from strips of sheet steel or other metal are bent to conform to outer surfaces of the beams or other construction materials are used to attach the beams to other beams or other construction materials. Fasteners or adhesive may be used to firmly attach the joints, connectors and/or brackets to the beams and construction materials.

This is a Divisional application of application Ser. No. 08/413,544,filed Mar. 30, 1995, now U.S. Pat. No. 5,692,353, which is aContinuation-in-Part of application Ser. No. 08/190,643, filed Feb. 2,1994, now U.S. Pat. No. 5,499,480, which is a Continuation-in-Part ofapplication Ser. No. 08/082,989, filed Jun. 25, 1993, now abandonedwhich is a Continuation-in-Part of application Ser. No. 08/040,494,filed Mar. 31, 1993 also abandoned.

BACKGROUND OF THE INVENTION

In recent years, the cost of lumber has increased dramatically as theresult of limitations placed upon the harvesting of trees in order topreserve the environment. Within the last few years alone, the cost oflumber has more than doubled. This cost increase has had a major impacton the cost of new residential construction, making new homes moredifficult to build and sell at affordable prices. This, in turn hasresulted in the decrease in new housing starts and increasedunemployment within the construction industry.

In addition to the increased expenses resulting from the high cost oflumber, there are other reasons that make it desirable to identify aviable alternative to wood for significant portions of the supportstructure in new construction. These reasons are related to thevulnerability of wood to insect damage and decay, and to the weight ofthe wood.

Pre-fabricated roof and floor trusses, and frame segments are well knownin the residential and light commercial construction industries. Thetrusses are most commonly formed from two-by-four studs joined togetherby steel gussets, while the frame segments are often nailed together.The pre-fabricated roof trusses are lifted onto and attached to the topof a structural frame so that the roofing material can be placed on it.The pre-fabricated floor trusses are attached to the foundation or thelower portion of the structural frame so that plywood and flooring canbe placed on top and attached thereto. The pre-fabricated components ofa structure provide substantial time savings in the constructionprocess, which can be critical when the climate in some areas permitsonly limited time windows suitable for construction. In general, thetime savings result in cost savings. Nonetheless, the significantincrease in the cost of lumber had made even these pre-fab trusses andframes so expensive that an alternative is being sought.

C-shaped or U-shaped lightweight steel beams or joists have long beenused for framing in light commercial structures and other lightconstruction. They also may have been used to a limited extent inresidential construction where, for example, a hollow beam is desired.The shape of these beams is defined by a base wall that is perpendicularto two parallel side walls. Each side wall may also have aninward-extending lip parallel to the base Wall and adjoining the edge ofthe side wall furthest from the base wall. The rectangularcross-sectional shape facilitates the use of such beams for framingstructures in a manner similar to that in which conventional woodenframing members are used. The steel beams, however, are difficult tointegrate with wooden framing members in a structure. The beams, unlessthey are relatively heavy gauge metal, can also be bent or crushedinadvertently during transport and while awaiting installation at aconstruction site. Moreover, they are less versatile than lumber, beingdifficult to configure into non-right angle joints.

Another disadvantage of C-joists is that they can only be roll formedperfectly straight, without any camber. Thus, no provision can be madefor normal deflection which occurs in floors constructed thereon due tocombinations of unsprung weight, applied live and dead loading, andlimitations on the allowable depth of the floor. It is, therefore,necessary to compensate for this lack of designed-in camber byincreasing the mass and thickness of the joist. This increases the costof the beam material itself as well as increasing the load factorsbearing upon the wall so that framing costs are also increased.

A lightweight steel beam has been developed by Navon which is describedin PCT Application Publication Number WO 9117328, based upon U.S. patentapplication Ser. Nos. 07/518554 (filed May 3, 1990) and 07/674549 (filedMar. 22, 1991). This structural beam is an I-beam of four piececonstruction, where the two bearing portions (top and bottom) have a"C"-shape and the web and flange portion consists of two pieces of sheetsteel which are welded at their centers and bent outward to form thetriangular flanges. This beam is illustrated in cross-section in FIG. 1,labeled "PRIOR ART". The flanges of the triangles are then welded to theinsides of the "C"-shaped bearing portions to create the I-beam. Twobeams are joined together by flat or angled gussets which are bolted orwelded to the outer surface of the web.

While the Navon beam provides an improvement upon conventional steelbeams since it is over 50% lighter and it is relatively easy to use inerecting a structure, it is not trivial to fabricate. Each beam consistsof four pieces which must be bent and welded together over the entirelength of the beam, making the production process one that requiresseveral specialized pieces of machinery and consumes time. Further, thejoints between two beams may be subject to excessive lateral stressessince the gussets merely attach to the outside of the web, withoutproviding any reinforcement of the joint by the beams themselves.

A further disadvantage of the Navon beam and similar metal I-beamconstruction materials is that the metal is an excellent thermalconductor. In a structure which has the beam spanning the width of awall, as the beams would normally be used, due to the continuous natureof the web, the temperature at the exterior surface of the wall isreadily conducted to the interior along the entire length of the beam.No amount of insulation between the interior and exterior sheet materialattached to the beam faces will eliminate this effect since the beamitself is the conductor. (The only effective insulation would have to beplaced between the beam face and the sheet material.) Since the Navonbeam is difficult to integrate with wood studs and other insulatingframing materials, the high thermal conductivity cannot be cured by usedof alternate materials within the structure.

SUMMARY OF THE INVENTION

It is an advantage of the present invention to provide a versatilelightweight steel beam system which may be used both in place of woodstuds and in conjunction with wood studs in construction.

It is a further advantage of the present invention to provide a systemfor fabricating roof, floor and other types of trusses and frames inwhich the steel beams are easily fitted together in any of a number ofdifferent configurations and angles.

Another advantage of the present invention is to provide a versatilelightweight steel beam system as an alternative to both wood andtraditional metal construction materials.

Yet another advantage of the present invention is to provide a metalconstruction system which has minimal thermal conduction betweenadjacent beams.

In an exemplary embodiment, the system for fabricating roof, floor andother types of trusses and frames begins with a beam or stud formed froma single piece of cold formed sheet steel which is bent lengthwise alongfour lines to form a triangular cross-section with two wings,side-by-side, extending from its apex. The two wings are not attachedtogether by a separate fastening means, but remain separable until thestud is joined to another stud or other type of construction material.This feature means that the beam or stud itself can become part of theconnection rather than just attaching a separate connector to an outersurface of the beam. This makes for much stronger joint as well asmaking assembly easier. For reinforcement of a long stud, notches may bemade in the wings, allowing wing segments to be folded over. (Note thatthe terms "beam" and "stud" may be used interchangeably. This isintended only as an indication that the inventive structure can be usedas either a stud (vertically-oriented frame component or a truss-member(horizontally-oriented frame component).)

A number of different means are provided to attach one stud to anotherat any angle. A combined gusset/tab connector has a first portion thatcan be inserted between the wings a first stud and a second portionconsisting of a plurality of tabs which are inserted through acorresponding slot in the second stud or other material to which thefirst beam is to be attached. The tabs are then bent so that they aresubstantially perpendicular to the plane of the first portion of theconnector and flush with the inner surface of the second stud. Animportant aspect of each connection means is that the joint formedbetween two beams or studs covers only a small fraction of the beam orstuds total length so that thermal conduction between the two componentsis minimized.

Brackets may be used which are constructed in a similar manner as thebeams, with triangular cross-sectional inserts or sleeves which fitwithin or over the stud, depending on the relative dimensions of thebracket's triangle and the stud's triangle. In one embodiment, thebrackets have a single triangle with an extended wing providing a gussetwhich is inserted between the two wings of one of the studs to beattached, and fastened in place by screws, bolts, or other fasteningmeans. The triangular portion of the bracket is inserted into the end ofthe second stud, or slid over the end, depending on whether thedimensions of the bracket triangle are less than or greater than thoseof the stud triangle. In another embodiment, the brackets have atriangle formed at two or more edges, to create a single wing extendingbetween the triangles. The triangles are inserted into or slid over theends of the studs to be joined, then fastened. To connect two studsend-to-end, a telescoping fitting consisting of a triangle with outerdimensions that are slightly smaller than the inner dimensions of thetriangle of the stud is used by inserting the telescoping connector intothe end of each of the two studs to be connected and driving fastenersthrough the studs and the telescoping connector. Similarly, a triangleof slightly larger dimensions can be used as a connector by sliding theconnector over the ends of the studs to be joined.

The assembly procedure, i.e., piecing, sizing, cutting, is the same asthat for a standard wood truss or frame, except that angle cuts on theends of the beams are not required to assemble the steel truss accordingto the present invention. The cutting of angles at the ends of the studsis eliminated by using brackets with built-in angles. The studs andconnectors can also be configured for use as wall studs for framing,door and window headers, and mobile home trusses.

Modifications to the basic stud can be used to create a number ofdifferent brackets for interconnecting multiple beams, to attach thebeams to wood studs, or to provide means for suspending other beams,studs or sheets of building materials from a support structureconstructed from the lightweight metal construction system. A sheerpanel can be formed using beams to provide superior sheer strength ascompared with similar panels constructed from wood or other metalconstruction materials.

One or more triangular studs can be partially embedded into sections ofwood studs, such that the wood provides the connection between the twobeams. The studs are firmly held within the wood by construction gradeadhesive. By using a number of wood sections of equal length disposed atintermittent points along a stud perpendicular to the stud, two studscan be joined in a parallel relationship to create a composite studwhich has the benefits of metal while still retaining wood surfaces towhich other materials can be nailed.

The sheet steel of which the beams, studs and brackets are formed can beselected according to weight requirements for a particular structure,with most common construction applications using material ranging from24 gauge to 8 gauge steel. Other materials, such as other metals (e.g.,aluminum or titanium) or high strength plastics, may be used accordingto the purpose of the structure. Wallboard or plywood can be nailed orscrewed to the base of the triangle, which is comparable in width to theedge of a two-by-four. Wood, plastic or other materials may also beinserted into the beam between the wings, to facilitate attachment ofother construction materials. The wings of the beam and the variousconnectors can be pre-drilled so that the fastener need only be insertedthrough the appropriate holes to achieve the desired connection.

BRIEF DESCRIPTION OF THE DRAWINGS

Understanding of the present invention will be facilitated byconsideration of the following detailed description of a preferredembodiment of the present invention, taken in conjunction with theaccompanying drawings, in which like reference numerals refer to likeparts and in which:

FIG. 1 is an end view of a lightweight steel beam of the prior art;

FIG. 2 is an end view of a lightweight steel beam according to thepresent invention;

FIG. 3 is a perspective view of a first embodiment of the bracket;

FIG. 4 is a side view of the bracket of FIG. 3 joining two beams;

FIG. 5 is a perspective view of a second embodiment of the bracket;

FIG. 6 is a side view of the bracket of FIG. 5 joining two beams;

FIG. 7 is a perspective view of a bracket for joining three beams;

FIG. 8 is a perspective view, partially cut away, of a bracket joiningtwo beams end-to-end;

FIG. 9 is a perspective view of a beam section for attachment to a woodstud;

FIG. 10 is a perspective view of an alternative extension for attachmentto a wood stud;

FIG. 11 is a side elevation of a bracket joining two beams side-by-side;

FIG. 12 is a side elevation of a bracket for joining two beams one overthe other;

FIG. 13 is a perspective view of a beam modified to provide additionalsupport;

FIG. 14 is a side elevation of a bracket for suspending a stud from abeam;

FIG. 15 is an end elevation of a bracket for supporting constructionmaterial above a beam;

FIG. 16 is a perspective view of a connector for joining two beams in aparallel arrangement;

FIG. 17 is a perspective view of a first joint for joining one beam toanother in a perpendicular arrangement;

FIG. 18 is a side elevation of a second joint for joining one beam toanother in a perpendicular arrangement;

FIG. 19 is an end view of the second joint;

FIG. 20 is a diagrammatic view of a frame section;

FIG. 21 is a cross-section taken along line 21--21 of FIG. 20;

FIG. 22 is a perspective view of a length of beam with an alternativereinforcement means;

FIG. 23 is a cross-section taken along line 23--23 of FIG. 22;

FIG. 24 is an end view of a reinforced beam;

FIG. 25 is an end view of an assembly for replacement of a wood stud;

FIG. 26 is a perspective view of a composite beam formed from two of thetriangular beams and wood;

FIG. 27 is a top view of a gusset/tab connector;

FIG. 28 is a perspective view of the gusset/tab connector of FIG. 27connecting two beams;

FIG. 29 is a roof truss constructed according to the present invention;

FIGS. 30a and b are an alternate connector for attaching a pair oftriangular beams to a wood stud, with FIG. 30a showing the connectoralone and 30b showing the connector with a wood stud;

FIGS. 31a and b illustrate a unitary wall stud constructed using theinventive construction system, with FIG. 31a showing a side elevationand FIG. 31b showing a cross-section taken along line B--B of FIG. 31a;and

FIG. 32 is a shear panel constructed according to the inventive system.

DESCRIPTION OF THE PREFERRED EMBODIMENT

It should be noted that components of the inventive lightweight metalconstruction system are described as having tops, bottoms and sides forreference only. These designations are not intended to limit theconstruction system to use in such an orientation.

As illustrated in FIG. 2, the basic lightweight steel beam or stud 2 istriangular in shape with a pair of wings 4 and 6 extending from the apex8 of the triangle 10. The triangle 10 is created by bending a sheet ofcold formed steel at four places: bottom corners 12 and 14 and shoulders16 and 18 so that the edges of wings 4 and 6 are generally even. Thetriangle 10 is symmetrical around a line drawn from the apex 8perpendicular to the base. The bottom corners 12 and 14 are slightlyrounded to avoid weakening the metal at the bends. No welding or otherfastening operation is performed on the stud 2, so the wings 4 and 6remain unattached until a structure is assembled. The wings areessentially flanges that facilitate attachment of the beams to thevarious connectors described below and are not intended to act as websas in a conventional I-beam. Therefore, typically, the wings need onlybe wide enough to support the fasteners driven therethrough and will besubstantially shorter than the heights of the sides of the triangle.Holes may be pre-drilled in the beam to facilitate insertion offasteners for connecting beams together.

The most basic connection means for attaching two studs together is agusset consisting of a flat piece of sheet material which is insertedbetween the wings of each of the beams to be attached. The sheetmaterial may be metal, ceramic, plastic, fiberglass, polymer, compositeor any other durable, high shear strength material. For joining beamsthat provide exterior to interior framing, an insulating material suchas ceramic, plastic, or glass-polymer composites, e.g., Micarta™, whichis manufactured by Westinghouse Corp., may be desirable to provide anon-thermally conductive joint. A roof truss utilizing a number ofdifferent gussets is illustrated in FIG. 29. The upper beams 340 and 342slope downward from peak 344, and are attached together near their lowerends by horizontal beam 346. To provide vertical support, four supportbeams 348, 350, 352 and 354 extend between upper beams 340 and 342 andhorizontal beam 346. At each joint, one or more connectors is used.

At peak 344, a gusset 356 is used to connect beams 340, 342, 350 and352. For additional stability gusset 356 is cut in a triangular shape.The upper edges of gusset 356 are inserted into the wings of beams 340and 342, which are oriented with their bases pointing upward and wingspointing downward. Fasteners 322 are driven through the wings of eachbeam 340 and 342 and the upper portion of gusset 356. The base of gusset356 is then inserted into the wings of beams 350 and 352 in which theupper ends have been cut at angles to allow the ends to be joinedtogether. Fasteners 322 are driven through the wings and base of gusset356 to attach the four beams together.

At joints 358 and 360, beams 348 and 354 attach to beams 340 and 342,respectively, at generally right angles. Since both joints are the same,only the joint between beams 342 and 354 will be described. Here, asquare gusset 362 is used in conjunction with a bracket 364. (Twoconnectors are illustrated to provide an example of use of connectors intandem and it is not intended to indicate that this particular jointrequires the reinforcement provided by two connectors.) Bracket 364 isinserted into the end of beam 354 with its open end facing upward.Flanges 366 extend upward at an angle that generally matched the profileof beam 342. Gusset 362 is inserted into beam 354 and into the openingin bracket 364 so that a portion of gusset 362 extends upward. Fasteners322 are driven through the sides and the wings of beam 354. Gusset 362is inserted into beam 342 and fasteners are driven through the wings ofbeam 342. Flanges 366 of bracket 364 are positioned on the outside ofbeam 342 and fastened.

The lower ends of beams 348, 350, 352 and 354 are attached tohorizontal-beam 346 by square gussets. For illustration, the jointbetween beams 348, 350 and 346 will be described. Gusset 368 is insertedbetween the wings of beam 346 so that it extends upward. Fasteners aredriven through the wings and the lower portion of gusset 368. The leftside of gusset 368 is inserted into the interior of beam 348 and theright side is inserted into beam 350, with fasteners being driventhrough the wings of both beams and though the gusset.

The joint between the upper beams 340 and 342 and horizontal beam 346 iscreated by triangular gusset 370 which is inserted into the upper andlower beams with fasteners being driven through the wings of each of thebeams to lock the gusset in place. In order to make the shallow angle,the upper edges of beam 346 are cut at a slant.

Beams 340 and 342 are of a length such that two separate beams may needto be pieced together. For illustration, beams 342a and 342b are joinedby connector 374. It is possible also to double up the function of aconnector in the joining of two beams end-to-end with other joints usinga gusset to make the end-to-end connection as well as an angledconnection such as at the intersection of beams 346, 348 and 350, wherebeams 346a and 346b are joined to make horizontal beam 346.

The shape of the gusset is generally dictated by the angle at which thebeams are to be joined. As shown in FIG. 28, although the beams 252 and253 are joined in parallel, rather than using a simple rectangle orsquare, the gusset 300 is shaped as a parallelogram so that it spans thespace between the beams at an angle while the ends 302, 304 of gusset300 still abut the inside surface of the bases of beams 252, 253. Thisangular configuration provides additional shear strength. For additionalstrength, ribs may be formed in the gusset parallel to the edges whichspan the space between the beams being connected. The connectorsillustrated in FIGS. 31a and b show such ribs 462, which may be stampedor roll formed into the sheet metal.

A significant advantage of using gussets, i.e., small pieces of sheetmetal inserted between the wings of the beams, for joining two beamstogether is that there is not continuous connection between the beamsfor the full length of the beams. The gussets are inserted only atcorners, or, where the beams are parallel, only at intermittent pointsalong the beam, similar to the composite beam of FIG. 28. The gusset isnot intended to be a substitute for the web of an I-beam, it is merely aconnector. The lack of continuous connection between two beams isimportant when considering insulation and thermal conduction inbuildings constructed with metal or partly metal frames. Minimal thermalconduction occurs where there is minimal connection between two beams.The space between the beams is, itself, a good insulator. However, theavailability of space allows the effective installation of insulation.Further, if the gusset is made of a non-thermally conductive material,conduction between the two beams is effectively eliminated.

One embodiment of the invention is a wall stud that can be substitutedfor a 2×4 wood stud to provide the inner and outer surfaces for mountingsheet material. This wall stud, illustrated in FIGS. 31a and b, issimilar to the composite beams of FIGS. 26 and 28, having twotriangular-cross-section studs 450 and 452 maintained parallel to eachother by connectors 454, 456, 458 intermittently spanning the spacebetween the two studs. The bases of the triangles, 451 and 453, providethe surfaces for attachment for the interior and exterior sheetmaterial. In this embodiment, the entire wall stud is formed from asingle piece of roll formed sheet metal. The space 460 between theconnectors are created by stamping or cutting the sheet metal. Theconnectors 454, 456, 458 have ribs 462 formed therein to provideadditional strength to the connection. This allows a standard-size wallstud, such as a 2×4, to be easily mass-manufactured while stillretaining all of the thermal and high-strength qualities of theinventive construction system. Since no connectors are required to formthe wall stud, the triangles remain open for easy attachment of thedifferent connection means disclosed herein.

One of the brackets for connecting two or more studs together are formedin a procedure similar to that used for the beams. As illustrated inFIGS. 3 and 5, the brackets 20 and 30 are formed by bending a sheet ofcold formed steel to form a triangle at at least one edge of the sheet.Describing bracket 20, the edges 22 and 24 of bracket are bent inward sothat they end at the apex 26 or 27 of the triangle without forming asecond wing as in the studs. The sheet is pre-cut so that the edges havethe desired angles. In this illustration, the sheet steel would betrapezoidal in shape. The dimensions of the bracket's triangles arepreferably slightly smaller than those of the beam so that they closelyfit within the beam's triangle. Alternatively, the bracket's trianglesmay be-larger than those of the beam, with the beam being inserted intothe bracket. A single wing 25 extends between the two triangles 21 and23, unlike the two wings created in formation of the beams. This allowsthe brackets to be formed from a single sheet with the fewest number ofbends possible, making their manufacture simple and economical. Nofastening of the bracket itself is required, the only fasteners beingapplied when the beams and brackets are assembled. The assembly of abracket 20 with two beams 2 and 2' is illustrated in FIG. 4. Fasteners40 are shown as sheet metal screws, but may also be welds, rivets orbolts. The brackets may be pre-drilled with holes to facilitateassembly.

Illustrated in FIG. 5 is a bracket 30 for forming the peak in a roof orsimilar angled construction by attaching two beams 2 and 2'. While theangle shown is relatively large, the bracket 30 can be formed to providevirtually any angle required. As described above for bracket 20, thesheet of cold formed steel is pre-cut to the desired angle, in this caseforming a hexagon. A notch 33 is made at the apex 35 to allow thetriangles to be formed independently of each other. The triangles 31 and31' are formed by creating three folds parallel to the angle-cut edges32 and 34, with the edges at the apex 35. The triangles 31 and 31' havesides slightly smaller than the inner dimensions of the triangle of astud. Alternatively, the dimensions of the triangles 31 and 31' can belarger than the outer dimensions of the studs so that the bracket isfitted over the outside of the end of the beam to be joined. The bracket30 and beams 2 and 2' are attached as shown in FIG. 6, with fastenersbeing driven through the wings of the respective beams and throughsingle wing 36 of the bracket. Alternatively, as with other connections,the pieces may be welded together. Holes may be pre-drilled for thedesired fasteners.

Three beams or studs may be joined together using a bracket of theconfiguration shown in FIG. 7. Edges 42 and 44 of the sheet metal arecut at the desired angles, then folded inward to form triangles 43 and45. Edge 46 is also folded inward to form triangle 47. As with bracket30, notches are cut between the individual triangles. The ends of thebeams to be joined are slid over the appropriate triangle and fastenedas above. The angles may be varied as needed by pre-cutting the sheetmetal.

Two studs may be attached together end-to-end by either inserting atelescoping-type connector bracket into the ends of each beam 2 and 2'or inserting the ends of the studs into the telescoping connector. Aconnection of the former type is shown in FIG. 8. The telescopingconnector bracket 62 consists of a triangular tube formed by bending asingle piece of sheet steel along three longitudinal lines intodimensions that are slightly smaller than the interior dimensions of thebeam triangle 10. Alternatively, the dimensions of the triangular tubecan be larger than the outer dimensions of the beam triangle 10 so thatthe bracket is fitted over the ends of the beams to be joined. Thebracket 62 should fit closely within the triangle 10 to provide optimalsupport. Fasteners 50 or welds are then used to attach each beam 2 and2' to the connector 62. As illustrated, the fasteners are driven throughthe respective wings of the connector and beams. Where the ends of thebeams are inserted into the telescoping connector, the triangle of theconnector has dimensions slightly larger than the outer dimensions ofthe beams.

The connector or end joint illustrated in FIG. 9 provides a first meansfor directly attaching a beam to a wood stud (or other constructionmaterial). The triangular portion 63 can be either a beam itself, or aconnector which telescopes with a beam, similar to the embodiment ofFIG. 8. In either case, the triangular portion 63 is formed in the samemanner as the beam of FIG. 2. Near the end of the beam, a section of thetriangle is cut away by making a lengthwise cut along each of the lowercorners 65 of the triangle, leaving only the base of the triangle. Thiscreates an extension 64 which is generally flat (except for curvature atthe edges 66 corresponding to the lower corners of the triangle). For a2×4 stud, the end of extension 64 is bent upward to create a space of 2inches between the location of the cut 66 and the upwardly bent end 68.The 2×4 stud is then fitted within the space, and fasteners such asnails or wood screws are used to attach the beam to the stud. Theextension 64 provides additional support and stability for a compositestructure made of beams and other construction material, such as, inthis example, wood studs. The space may be adapted to fit anyconstruction material by adjusting the location of the cut 66 and thebend 67.

An alternative embodiment of the end joint of FIG. 9 is illustrated inFIG. 10. This embodiment differs from that of FIG. 9 in that thetriangular portion 72 is formed after the extensions are defined. A flatsheet of stainless steel is cut to remove two end sections from widthL1, leaving a section of width L2, which equals L1 less the outer widthof the triangular portion 72 (shown unfolded by the dashed lines).

A lengthwise cut is made in from the ends along a line that will be thefirst corner 75 of the triangular section 72, leaving extension 76 and77 with width L3. The metal sheet is then folded lengthwise to createcorner 75. The center portion is folded lengthwise again to form corner78 and bent at line 79 to form a lip 80. End tabs 81 and 82 are foldedinward, against the ends of triangular section 72 to provide additionalstrength and to provide means for attachment to one side of a 2×4 studor other construction materials. As an example, tab 82 is shown withwood screws through it for attachment to stud 84 (shown in dashedlines). Stud 84 fits within a space between tab 82 and extension end 86,which is bent upward to be parallel to tab 82. Fasteners may be driventhrough the outside of end 86 into stud 84. (As in other components,holes may be pre-drilled in the metal to facilitate assembly.) Extension76 is shown without an upwardly bent end. In this configuration,attachment to a wood stud (not shown) can be accomplished by drivingfasteners upwardly through extension 76 and outwardly through tab 81. Bynot bending up the end, connection can be made to a large beam or otherlarge dimension structure, e.g., the edge of a concrete block. Thecombination of tab 81 and extension 76 can also be bent to create acurved contact surface for attachment to pipes or other roundedsurfaces. An end joint configured as that shown in FIG. 10 retains theadvantages of high strength and simple manufacture of thetriangular-beam while providing versatility for adaptation to otherbuilding surfaces.

A second means for attaching a pair of triangular beams to a wood studis illustrated in FIGS. 30a and b. This type of connector could be usedto attach vertical beams to a 2×4 header, for example. A separateconnector 400 has two sections--a first section 402 which is bent tocreate partial triangular profiles for fitting over a portions of theexterior of each of beams 404 and 406 (shown with dashed lines in FIG.30a). Fasteners may be driven through the wings of the respective beamsand through the first section 402. The wood stud 408 (shown in FIG. 30b)to which the beams are to be attached is butted against the inside end409 of the first section 402, between arms 410, 412. The dimensions ofthe connector 400 are such that it closely fits the wood studdimensions, e.g., 4 inches between the arms for a 2×4 stud. With thestud 408 in place, arms 410, 412 are bent to wrap around the stud, withends 414, 416 contacting the side of the stud opposite that abutting thefirst section 402. Holes 418, 420 may be pre-drilled or pre-cut tofacilitate attachment to the stud 408 by driving nails, screws, or otherappropriate fasteners through the holes and into the wood.

The bracket 90, illustrated in FIG. 11, is formed from a strip of sheetsteel and may be of any length for use in connecting two neighboringbeams. At each end of bracket 90, the metal is bent laterally to conformto the outer shape and dimensions of the beams to be joined. Here, bothbeams 92 and 94 are oriented in the same direction, with bases 96 and 97facing downward. The ends of bracket 90 are bent to conform with thesides of the beams 92 and 94 and then bent downward at the center towrap around the wings 98 and 99 of the beams. Fasteners, here, machinescrews 100, are driven through the bracket and wings of each beam. It ispossible to join a string of beams by continuing the extension 93 ofbracket 90 for whatever length is needed, bending the bracket to conformto the upper profiles of the beams for each beam to be joined. Forexample, if a third beam were to be attached between beams 92 and 94,three lateral bends would be made in the center of extension 90 toconform to the wings and sides of the third beam.

Bracket 102, illustrated in FIG. 12, is used to join two beams whichhave their wings 104 pointed toward each other so that the two beams areparallel (only one beam is shown). Similar to previous brackets, bracket102 is formed by making lateral bends in a strip of sheet steel. Each ofthe ends 106 and 107 of bracket 102 wrap around the side 108 and base109 of the beam 103, and may have a lip 110 extending partially up side111, so that each end 106 and 107 will cradle the beam. The ends 106,107 may be extended along the beam's length to provide a greater contactsurface area. A fastener 112, here, a sheet metal screw, may be driventhrough the bracket 102 and wings 104 to secure their relativepositions. The extension 105 between the two triangular sections may bewhatever length is needed to span the two beams.

The gusset/tab connector 248 for joining a first beam perpendicular to asecond beam or other construction material, such as a C-shaped beam orsheet material, is illustrated in FIG. 27. The gusset/tab connector 248is a flat piece of sheet steel which is cut with two or more tabsextending from one side. The first portion 250 has flat edges and isinserted between the wings of vertical beams 252, 253 shown in FIG. 28.Gusset/tab connector 248 may be attached to the vertical beams 252, 253by welding or by suitable fasteners. The second portion 256 has tabs 257and 258 formed therein. The tabs may be formed by stamping or cuttingthe sheet metal. Notches 260 are provided to facilitate bending of thetabs.

Tabs 257, 258 are inserted through a slot 262 in a horizontal beam 264so that first portion 250 is on a first or outer side of the horizontalbeam and the tabs are on the second or inner side. (The horizontal beam264 is illustrated as a C-beam.) The tabs 257, 258 are bent in oppositedirections, so that each is perpendicular to the first portion 250 andflush with the inner surface 266 of beam 264. Only one, or more than twotabs can also be used to create such a connection. Where there aremultiple tabs, the adjacent tabs may be bent in opposite directions. Thetabs may be welded to inner surface 266, or fasteners may be driventhrough pre-cut holes 268, 269.

In FIG. 13 a means of reinforcing a lengthy beam is illustrated. When abeam is several meters long without support or some connection at itscenter, forces on the ends of the beam may cause the beam to gape at thecenter. This gaping can be alleviated by cutting a section 112 in onewing 114 and folding to over the other wing 116, thereby providing meansfor holding the wings together without requiring additional fasteners.As illustrated in FIG. 13, wing 114 is longer than wing 116 tofacilitate this reinforcement procedure. Alternatively, a notch can bemade in wing 116 to allow section 112 to be folded over when wings 114and 116 are the same length.

Another means for reinforcing a lengthy beam is illustrated in FIGS. 22and 23. A generally U-shaped cut 204 is made through both wings 200 and201 of the beam to form a tongue 202. The tongues 202 from each wing arepressed together through both cut-outs and bent back around the outerside of the wing, as shown in FIG. 23. Alternatively, the inner tongue(as illustrated, the tongue on the right wing) can be cut off and theremaining tongue bent across as shown. The shape of the cut-out is notlimited to a U-shape, but can be any cut which creates a tongue-likeprotrusion in one wing which may be bent through the cut-out in theadjacent wing to hold the two wings together.

A third means for longitudinally reinforcing the beam is shown in FIG.24. Here, grooves 210 are formed in the sides 212 and base 214 of thetriangle to provide additional strength against bending or gaping. Bypressing or bending the metal surfaces. For ease of manufacture, thegrooves are formed before the triangle itself is created. This way,large sheets of corrugated metal can be formed, then cut as needed tomake the triangular beams.

FIG. 14 illustrates a bracket 118 for suspending a wood stud 120, orother type construction material, including other beams, from a beam122. Bracket 118 is a strip of sheet steel which is bent laterally fivetimes to form a generally triangular cross-section at its upper portion,including an open slot 124 into which the wings 126 of beam 122 fit. Thetwo extensions 128 of bracket 118 can be as long or as short as neededto permit proper spacing between the stud 120 and beam 122. Screws 130,or other fastening means are used to fix the stud 120 within the bracket118. Stud 120 need not actually be suspended from beam 122, but canmerely be supported at its upper end by the beam 122 and bracket 118.

The bracket 132 shown in FIG. 15 is used for attaching constructionmaterials (not shown) within space 134 to a beam (not shown), the top ofwhich fits within generally triangular section 136, similar to therelationship between the beam and connector shown in FIG. 14. Bracket132 is formed in the same general manner as other brackets. Space 134may be expanded to accept a wood stud or other materials, a fastener(not shown) may be driven through extensions 138 to affix the materialto the connector 132, similar to that shown in FIG. 14.

The end joint 140 illustrated in FIG. 16 may be a separate connectingpiece or may be a modified end of a full beam which allows one beam tobe directly attached perpendicular to a second beam. Here, it is shownas a separate connecting piece. End joint 140 is of the sameconstruction as is the basic beam (as in FIG. 2). Lengthwise cuts aremade along the lower corners 142, 143 of the triangle and the wingportions above the triangle are removed. The side flaps 144, 145 arebent away from the extended base 146 at the same angle as the side of abeam. Here, beam 148, shown in dotted lines, illustrates therelationship between the bent-back side flaps and the side of the beamto which the end joint 140 attaches. Extended base 146 supports thebottom (base) of beam 148, while the side flaps 144 and 145 contact theside 150 of the beam 148. Fasteners (not shown) may be driven throughthe base 146 and the side flaps 144 and 145 into beam 148 to firmlyattach the end joint 140 perpendicular to the side of the beam 148. Atthe opposite end of the end joint 140, no beam is shown, but the flaps144' and 145' and base extension 146 are ready to be attached to anotherbeam which will then be parallel to beam 148.

The end joint shown in FIG. 17 may be formed either in a separateconnector or at the end of a beam. Here, the joint is shown formed atthe end of beam 152 which is to be attached perpendicular to beam 154.To form the joint, a basic beam is cut with a lengthwise cut 158 intothe center of the base 156 for a distance approximately equal to theheight of beam 154. Adjacent the lower part of the cut, the corners 157are bent away from the base 156 to create a triangular openingcorresponding to the cross-section of beam 154, with flaps 153 abuttingsides 161 of beam 154.

A second cut 159 is made laterally across both wings 160 and the lowercorners 162 are bent outward to create a triangular openingcorresponding to the cross-section of beam 154 with flaps 163 abuttingsides 161 of beam 154. The beam 152 is fitted down over beam 154 makingsure that the wings 164 are fully seated within cut 158. Fasteners 165may be driven through the flaps 153 and 163 and into sides 161.

FIGS. 18 and 19 illustrate an alternate joint for attaching the end ofone beam to the top of another. This joint differs from that of FIG. 17in that the wings of the two beams do not meet. Instead, the wings ofthe beam to which the beam 170 is to be joined are inserted into slots174. Slots 174 are formed by cutting lengthwise in from the beam endinto sides 170 and bending the corners of the slots 174 back to createflaps 176 and 178. The flaps 176 and 178 are bent back to create atriangular opening with dimensions corresponding to the triangularcross-section of a basic beam, such as shown in FIG. 2. Once the jointis fitted over the beam to which beam 170 is to be attached, fasteners(not shown) may be driven through flaps 176 and 178 into the sides ofthe adjoining beam to provide a strong connection between the beams.

FIGS. 20 and 21 show a support brace 180 which may be used to addstrength to a structure which has extended lengths of beams. Brace 180is a strip of metal with L-shaped ends 182 which wrap around the beams184 and 186 and are fastened to each of the beams, generally locatedabout half between the ends of the beams. FIG. 20 illustrates a sectionof frame in which the inventive beams provide the vertically runningportions (beams 184 and 186) attached to a 2×4 wood stud 188 at the baseby the end joint 192, as in FIG. 9. At the tops of the beams is attacheda third metal beam 190, which is attached using the end joint 194 as inFIG. 17.

In the preferred embodiments, the width of the base of triangle 10 of abeam is comparable to that of a two-by-four stud, so that anything thatwould have required support from the edge of a stud, such as wallboard,plywood or roofing material, will be similarly supported by the beam 2.Similarly, where specialized connectors are described above for use withwood studs, the inventive beams may be substituted for the stud. Nailsor other fasteners may be driven through any side of the triangle 10 toattach material which is to be supported. Other building materials mayalso be inserted between the wings 4 and 6 and into a beam. For example,a two-by-four stud can be inserted by spreading the triangle to providea wood surface for nails. Similarly, plastics or composite buildingmaterials may also inserted into the beams. Where appropriate, differentsize beams can be used which are larger than or smaller than thedimensions of a typical 2×4.

The combination of beams illustrated in FIG. 25 is an alternative to a2×4 wood stud (or other standard wood construction beam), possessing thefeatures that will allow other construction materials to be directlyattached. This "metal 2×4" is formed from two asymmetrically benttriangular beams 220 and 222 which have legs 221 and 223 extending fromthe apexes to form a flat surface 226 comparable to the 2 inch edges ofa 2×4 wood stud into which fasteners may be driven to support otherconstruction materials. The two beams 220 and 222 are joined together bya generally L-shaped connector 228 which is attached to the inside wing230 of each beam by welding or some other fastening means (welds areshown but not labeled). For attachment of construction materials to thebroader side of the beam, fasteners may be driven through the bases 232and 234 of the two triangles. As an example of the use of this "metal2×4", it may be used to replace the wood stud 84 illustrated in FIG. 10.Leg 221 of the "metal 2×4" would be attached by fasteners to extension77, and screw can be driven through end tab 82 into base 232.

FIG. 26 illustrates a composite beam formed from two triangular beams300, 302 which are joined together by sections of wood stud 304, and306. The wood is cut with a triangular indentation and a slot to fitclosely over the sides 308, 309 and wings of the beams. When the beam isembedded into the wood section, the base 310 of the triangle thenbecomes the end face of the wood stud, since it is essentially flushwith the end of the stud. A construction grade adhesive, such as thatused for attaching wood flooring or wall panelling, is used topermanently attach the two pieces together.

The lengths of the wood stud sections 304, 306 can be selected toprovide, for example, the standard spacing between wall studs in aninterior wall. The wood stud sections can be spaced at regularintervals, or in any manner to facilitate the construction process, suchas appropriate spacing for installation of a window or pass-through, orfor placement of recessed cabinets. Using the composite beam, theadvantages of the metal beam are obtained while still retaining asubstantial amount of wood surface to which sheet material or otherobjects may be nailed. (For example, it would be more secure to hang aheavy picture on the wall of a structure with the inventive frame ifthere is a wood beam available for placing picture hangers.) A compositebeam may also be used to form an exterior wall, with beam 300 againstthe exterior surface and beam 302 against the interior surface. The woodinsulates the exterior beam from the interior beam so that there is nothermal conduction between the two.

FIG. 32 illustrates a shear panel 500 constructed using the beams, studsand connectors as disclosed above. Beams 501-504 form the outer frame ofthe panel. Gusset 505 is inserted between the wings of beams 501, 502and 503, and gusset 506 is inserted between the wings of beams 501, 503and 504, Brackets 507 and 508 are formed as in the embodiment of FIG. 17with a length equal to that of beams 502 and 504 and slits cut in eachend to fit over the wings of beams 501 and 503. The wings of eachbracket are fitted over the exposed edge of corresponding gusset 505 or506. Fasteners are driven through the ends of brackets 507 and 508 andthrough the wings of the beams and the corresponding gusset. The web ofthe shear panel is formed by combining brackets, formed as in theembodiment of FIG. 17 with slits at each end, and gussets, with twobrackets per gusset so that the gusset is sandwiched between the wingsof both brackets. The web sections 510-513 are disposed at angles lessthan 90 degrees to the beams 501, 503 so that the web has a zig-zagconfiguration. The ends of the brackets of each web section are fastenedto the wings of beams 501 and 503 using rivets, sheet metal screws orother appropriate fasteners. The dimensions of the beams and bracketscan be different from each other. For example, the beams 501-504 can bemade from 16 gauge steel with triangle dimensions of 2"×2"×2", while thebrackets can be 18 gauge steel with dimensions of 1.5"×1.5"×1.5". Thegussets can also be made from 18 gauge steel.

The material of which the beams and various brackets are made can beadapted to fit the demands of the construction project. Cold formedsteel ranging from 24 gauge to 8 gauge can be used, as well as othermetals such as aluminum, titanium and numerous steel alloys. For mostcommon construction purposes, steel will likely be the material ofchoice.

The connectors and brackets described above permit the formation ofvirtually any angle required for building a structure without requiringangle cuts to be made in the ends of the beams. This is of particularimportance where the training level of the construction personnel issuch that angle cuts are a frequent source of errors.

The inventive beams, studs, brackets and assembly method can besubstituted for traditional two-by-four framing studs, door and windowheaders, and any number of other applications for which wood framing istraditionally used, or the metal construction system can be integratedwith wood frame components. The lightweight steel beam system isinexpensive to manufacture and is as easy to assemble and handle astraditional wood construction. The use of steel beams as an alternativeto wood addresses an issue that has had significant impact on theconstruction industry, providing a high quality, environmentally safematerial. Further, the steel beams are immune to many of the problems ofwood construction, since insect damage and wood rot are not of concern.Finally, the use of the simple triangular beam with connectors locatedonly at joints or support points along their lengths avoid a significantdrawback of prior art metal I-beam construction materials and C-joistssince thermal conduction between two connected beams is minimized orcompletely eliminated, depending on the type of connection.

It will be evident that there are additional embodiments which are notillustrated above but which are clearly within the scope and spirit ofthe present invention. The above description and drawings are thereforeintended to be exemplary only and the scope of the invention is to belimited solely by the appended claims.

It is claimed:
 1. A lightweight metal construction system comprising:aplurality of beams, each beam formed from sheet metal as a triangulartube having a base, two sides and two wings corresponding to each sideof said two sides extending from an apex of said triangular tube, eachsaid beam having a beam length, an inner beam surface and an outer beamsurface and being openable between said two wings; a plurality ofconnectors for connecting two beams of said plurality of beams to aconstruction material having an upper surface, a lower surface, and atleast one side surface, wherein said two beams are spaced apart at aspacing with their respective apexes facing each other, each connectorof said plurality of connectors having at least one tab portionextending from said base of each said two beams so that when an end ofeach said two beams is abutted against said lower surface of saidconstruction material, said at least one tab portion extends beyond saidupper surface of said construction material so that said at least onetab portion may be bent flush with said upper surface; and a pluralityof fastening means for fastening said plurality of connectors to saidconstruction material.
 2. A lightweight metal construction system as inclaim 1, wherein each said connector further comprises a base portionconnected to said at least one tab portion, said base portion extendingto abut said outer beam surface of at least one of said two wings ofeach said two beams, at least one of said two sides of each said twobeams, and said base of each said two beams.
 3. A lightweight metalconstruction system as in claim 2, wherein said at least one tab portionis bendable so that at least a portion of said at least one tab portionis flush with both said at least one side surface and said upper surfaceof said construction material.
 4. A lightweight metal constructionsystem as in claim 1, wherein said at least one tab portion has a holetherethrough for facilitating placement of a fastening means of saidplurality of fastening means.
 5. A lightweight construction system as inclaim 1, wherein said two beams are formed from a single piece of sheetmetal so that they are pre-joined in a parallel relationship to eachother.
 6. A lightweight construction system as in claim 5, wherein saidbase of each said two beams extends beyond said beam length forming abase tab.
 7. A lightweight metal construction system as in claim 6,wherein said base tab of each said two beams is bendable so that atleast a portion of said base tab of each said two beams is flush withsaid upper surface of said construction material.
 8. A lightweight,lumber-compatible metal construction system comprising:a plurality ofsheet-metal beams, each beam of said plurality of sheet-metal beamsformed as a triangular-shaped tube openable at an apex and having abase, two sides adjacent said base and angled inward towards said apex,and two wings corresponding to said two sides and extending from saidapex in a plane perpendicular to said base, each said beam having a beamlength, an inner beam surface, and an outer beam surface; a plurality ofconnectors for connecting a first beam and a second beam of saidplurality of sheet-metal beams to a construction material, said firstbeam and said second beam having respective apexes facing each other,wherein said first beam and said second beam are abutable against afirst side of said construction material, each connector of saidplurality of connectors comprising at least one tab extending beyondsaid base of each said first beam and said second beam so that said atleast one tab is bent flush with a second side of said constructionmaterial, wherein said at least one tab is parallel to said base; and aplurality of fastening means for fastening said at least one tab to saidconstruction material.
 9. A lightweight, lumber-compatible metalconstruction system as in claim 8, wherein each said connector furthercomprises a base portion which extends to abut at least one of said twowings of each said first beam and said second beam, at least one of saidtwo sides of each said first beam and said second beam, and said base ofeach said first beam and said second beam.
 10. A lightweight,lumber-compatible metal construction system as in claim 8, wherein saidat least one tab has a hole therethrough for facilitating placement of afastening means of said plurality of fastening means.
 11. A lightweight,lumber-compatible construction system as in claim 8, wherein said firstbeam and said second beam are formed from a single piece of sheet metalso that they are pre-joined in a parallel relationship to each other.12. A lightweight, lumber-compatible construction system as in claim 11,wherein said base of each said first beam and said second beam extendsbeyond said beam length forming a base tab.
 13. A lightweight,lumber-compatible metal construction system as in claim 12, wherein saidbase tab of each said two beams is bendable so that at least a portionof said base tab is flush with said second side of said constructionmaterial.